Impact of repetition time in 3D-real IR MRI sequences on inner ear imaging after single-dose gadobutrol: a comparative study in ménière's disease.

OBJECTIVE

To compare short (TR = 7000 ms) and long (TR = 10000 ms) repetition time 3D-real inversion recovery (IR) sequences with 3D-FLAIR MRI in terms of image quality and diagnostic performance for evaluating endolymphatic hydrops (EH) after a single intravenous dose of gadobutrol in patients with unilateral Ménière's disease.

MATERIALS AND

METHODS

Thirty-seven patients with definite unilateral Ménière's disease underwent inner ear MRI 4 h after administration of gadobutrol (0.1 mmol/kg). Each patient was scanned using 3D-real IR sequences with two different TR values (7000 ms and 10000 ms), as well as a conventional 3D-FLAIR sequence. Quantitative image analysis included contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR), while qualitative scoring and inter-/intra-observer agreement were also assessed.

RESULTS

The short TR (7000 ms) 3D-real IR sequence failed to demonstrate adequate perilymphatic enhancement in most cases. In contrast, both the long TR (10000 ms) 3D-real IR and 3D-FLAIR sequences consistently visualized perilymphatic enhancement and EH. The TR = 10,000 ms sequence provided significantly higher image quality metrics (CNR and SNR, P < 0.001), particularly improving detection in the cochlear apex. It also showed better inter-observer agreement than 3D-FLAIR.

CONCLUSION

The 3D-real IR sequence with a TR of 10,000 ms offers superior image quality and enhanced diagnostic confidence for EH evaluation compared to both the shorter TR sequence and conventional 3D-FLAIR. These findings support the use of a longer TR protocol for inner ear MRI following single-dose gadolinium administration in clinical settings.